The present invention relates to a sieve device for cleaning molten plastics.
A sieve device for cleaning molten plastics in conjunction with a high-pressure press and consisting of a housing with a flow-through bore that constitutes part of the flow channel of the high-pressure press and of a plate or disk that can be displaced or rotated in the housing and that has several perforations, at least one of which is always in the vicinity of the flow channel and at least one of which is always outside the housing, whereby either a sieve disk is always positioned inside the flow channel or sieve disks are positioned inside the perforations is in itself known.
The perforations in the plate or disk that can be displaced or rotated in the housing of sieve devices of the generic type are in accordance with the purpose for which the device is intended introduce alternately into the flow channel of the high-pressure press.
Every time a new perforation enters the vicinity of the flow channel the pressure conditions that the molten plastic is subject to changes because the air in the perforation entering the flow channel has to be compressed by the molten plastic. This necessity has also always led in unfavorable conditions to the formation of bubbles in the molten plastic because part of air in the perforation gets included in the plastic.